Snap-in fastener and apparatus for molding same

ABSTRACT

The present invention relates generally to improvements in fasteners adapted for snap insertion within a work aperture, and more particularly to improvements in snap-fasteners of multipiece form. The embodiment of the invention disclosed herein comprises a headed shank member and a sleeve member telescopically associated therewith. The sleeve member is secured in pre-determined spaced relation with respect to the work engaging side of the head and incorporates a laterally yieldable section to permit telescopic association thereof with a work aperture. The spacing of the sleeve with respect to the head is dependent upon a pre-selected lineal dimension of the shank, such dimension being determined by the thickness of the work to which the fastener is to be applied.

United States Patent 1 May 30, 1972 Ryder [54] SNAP-IN FASTENER ANDAPPARATUS 3,093,027 6/1963 Rapada .155 R FOR MOLDING SAME PrimaryExaminer-Edward C. Allen [72] Inventor. Francis E. Ryder, Mt. Prospect,Ill. Attorney olson, Trexler, woke & Bushnell [73] Assignee: ValueEngineered Components, Inc., Lake Zurich, Ill. [5 7] ABSTRACT [22]Filed: Mar. 20, 1970 The present invention relates generally toimprovements in [211 App]. No: 21,444 fasteners adapt ed forsnapinsertion with n a work aperture, and more particularly to improvementsin snap-fasteners of multi-piece form. The embodiment of the inventiondisclosed [52] US. Cl ..85/5, 249/ 158 herein comprises a headed shankmember and a sleeve [51 Int. Cl ..F 16b 21/08 mber telescopicallyassociated therewith, The sleeve of Search 3 S, 80, 5 R; D, member isecured in predetermined spaced relation 24/ 73 HS respect to the workengaging side of the head and incorporates a laterally yieldable sectionto permit telescopic association [56] References C'ted thereof with awork aperture. The spacing of the sleeve with UNITED STATES PATENTSrespect to the head is dependent upon a pre-selected lineal dimension ofthe shank, such dimension being determined by 2,943,373 7/1960 Rapata..85/80 the thickness f the work to which the fa t is to be 2,882,780 41959 Edwards. ....85/5 R pliei 861,573 7/1907 Budd ....85/5 R I2,650,516 9/1953 Poupitch ..85/5 R 8 Claims, 9 Drawing Figures Z J0 l' l5 X I N Z6 3i W lui' i JB I 5 J6 30 l .14

Patented May 30-, 1972 3,665,800

2 Sheets-Shawl; 1

- Francis E Ryder 0/500, Trex/er, Wo/fers 8 Bus/me A n 'ys Patented May30, 1972 3,665,800

2 Sheets-Sheet 2 L Franc/'5 E Ryder BY J 3 Olson, Trexler, Walters 8Bushnell AH'ys SNAP-IN FASTENER AND APPARATUS FOR MOLDING SAME Snap-intype fasteners have heretofore been employed wherein a one-piece moldedstructure includes a head, a shank, and an entering extremity formedwith laterally yieldable shoulder to permit telescopic association ofthe one-piece fastener with an apertured work-piece. Obviously, theaxial spacing of the shoulder with respect to the work engaging side ofthe head is predetermined to accommodate a workpiece of correspondingpre-determined thickness. To provide, as by molding, a similar fastenerfor a workpiece of different thickness necessitates the provision of aseparate die in which the cavity details for the head, shank length, andentering extremity of the resulting fastener must be incorporated. Ithas been found, for example, that overthickness of a workpiece such as apanel may result from the presence of a burr, paint, plating, etc. Undersuch circumstances, it may be impossible to employ the one-piecefastener which was originally designed for a given workpiece thickness.To inventory a supply one-piece type fasteners to accommodateworkthickness variations of the type just referred to would be mostimpractical and exceedingly costly.

It is one of the important objects of the present invention to provide amulti-piece fastener of the type referred to above, which is soconstructed that the axial spacing of the work engaging side of afastener head may be produced without the necessity of providing acompletely new or separate die for each size.

It is a further object of the present invention to provide a multi-piecesnap-in fastener of the type referred to above, wherein workpieces ofdifferent thicknesses may be accommodated by the simple expediency ofaltering the length of the shank portion of the fastener.

Another objectof the present invention is to provide a novel and verypractical snap-in fastener in which a sleeve member or thimbletelescopically associated with the fastener shank may be of uniform sizeand contour regardless of the workpiece thickness with which it is to beused. Thus a quantity of such parts may be inventoried for use withcomplementary shank members of varying lengths.

The present invention also contemplates a new and improved injectiontype molding apparatus for molding the shank section of a two-piecefastener whereby shank sections of varying lengths may be molded veryeconomically.

The foregoing and other objects and advantages will be more apparentfrom the following detailed description when considered in connectionwith the accompanying drawings wherein:

FIG. I discloses a two-piece fastener, shown partly in section, which isrepresentative of one-embodiment of the present invention, said fastenerbeing shown in telescopic association with a work aperture;

FIG. 2 discloses the fastener as viewed from the bottom of FIG. 1;

FIG. 3 is a fragmentary sectional view taken substantially along theline 3-3 of FIG. 1;

FIG. 4 is an elevational view disclosing the fastener parts in separatedrelation;

FIG. 5 is a detailed, sectional view similar to FIG. 3 disclosing amodified form of sleeve wherein circumferentially distributed ribsextending radially inwardly from the inner periphery of the sleeveengage the outer periphery of the shank section and thus lend lateralstability to the sleeve;

FIG. 6 is a detailed sectional view similar to FIG. 5, showing thetemporarily distorted condition of the sleeve member during the initialinsertion thereof within a work aperture;

FIG. 7 is a central sectional view of the headed shank section inassociation with the mold cavity and the longitudinally adjustablecentral core member;

FIG. 8 is a view similar to FIG. 7, disclosing the core member shiftedto the right whereby to enable molding a headed shank member ofincreased length; and

FIG. 9 discloses a snap-in fastener having a head of modified form.

Referring now to the drawings more in detail, wherein like numerals havebeen employed to designate similar parts throughout the various figures,it will be seen that a two-piece fastener which is representative of oneembodiment of the present invention is designated generally by thenumeral 10. The fastener 10 is composed of twoparts, namely: a headedshank member 12 and a sleeve or thimble member 14. The shank member 12includes a shank section 16 and a head section 18 molded integraltherewith. The head section 18 as shown in FIGS. 1 and 4, is formed soas to provide an axially flexible outer margin. Immediately beneath thehead 18 is an enlarged shank portion 20, the diameter of whichapproximates the diameter of a complementary aperture 22 in a pair ofabutting worksheets or panels 24 and 26.

The sleeve or thimble 14 has a tapered body protion 28 and three equallyspaced longitudinal ribs 30 projecting radially outward from the"periphery of the tapered body 28. The smaller extremity of the sleeve 14has an internal diameter conforming substantially with the diameter ofthe entering extremity of the shank member 16. A shoulder 32 on theshank member 16 cooperates with a complementary internal shoulder 34 ofthe sleeve 14 to limit the extent to which the sleeve may betelescopically associated with the shank member. When the shoulders 32and 34 are in abutment, the portion of the shank member extending beyondthe extremity of the sleeve 14 may be upset so as to provide an annularinterlock with the entering edge of the sleeve as clearly shown inFIG. 1. When thus assembled, the sleeve 14 is secured in predeterminedspaced relation with the underside of the head 18.

It will be noted that the three uniformly spaced ribs 30 at the trailingextremity of the sleeve 14, normally define a circle which is largerthan the work aperture 22. Each of the ribs 30 taper toward the enteringend of the fastener, and in fact, merge with the external periphery ofthe sleeve. Thus as the preassembled fastener elements are initiallyinserted within the work aperture 22, the ribs 30 will be forcedradially inward until the head 18 yieldably engages the outer surface ofthe work panel 24. Upon clearing the aperture 22, the locking ribs 30will spring radially outwardly to their normal position shown in FIGS. 1to 4 inclusive, thereby firmly securing the work panels 24 and 26 inabutting relation. The shank enlargement 20 maintains the co-axialrelation of the fastener with the aperture, and affords the requireddegree of shear strength. Both the shank member 16 and the sleeve 14 arepreferably formed of suitable plastic material which affords the desireddegree of strength and firm resiliency.

In FIGS. 5 and 6 a fastener sleeve or thimble of slightly modified formis shown. This sleeve is designated generally by the numeral 14a, andincludes a tapered body 28a and equally spaced ribs 30a, correspondingwith the previously mentioned body and ribs 28 and 30 respectively. Theonly structural difference between the sleeve 14 and the sleeve 14a isin the provision of inwardly projecting, uniformly spaced protuberancesor ribs 36. In their normal relation the inner extremities of the ribs36 define a circle having a diameter substantially equal to the diameterof the shank member 16. During the initial telescopic assembly of thesleeve 14a, with the work aperture 22, the engagement of the outersurfaces of the ribs or longitudinal protuberances 30 with the walldefining the aperture 22 causes the tapered body 28a to assume the shapeillustrated in FIG. 6. Thus the inner extremities of the protuberances36 are out of engagement with the periphery of the shank member.However, when the fastener has been completely inserted, the ribs 36aspring outwardly and the ribs or protuberances 36 spring inwardly, so asto occupy the position shown in FIG. 5. The engagement of theprotuberances 36-with the periphery of the shank counteracts anytendency for the sleeve or thimble 14a to tilt with respect to the shankaxis. In other words, the sleeve is maintained in axial alignment onceit has been completely inserted within the work aperture.

One of the distinct advantages of the present invention resides in theprovision of a sleeve or thimble which need not be varied in size orcontour for accommodating work of various thicknesses. .As previouslymentioned, snapin fasteners of the one-piece molded type present thedisadvantage of requiring a completely separate mold or die for eachvariation in space between the head which engages one side of the workand the shoulder engaging the opposite side of the work. To accomplishthis the present invention contemplates the use of shank members ofvarying length to accommodate differences in work thickness. In FIG. 7 amold is disclosed which includes a section 38 which. is longitudinallyapertured to accommodate a core member 40. The extremity of the core 40is provided with a cavity 42 shaped in conformity with the shank section16. The distance indicated by the letter A in FIG. 7 is critical becauseit is this dimension which ultimately determines the space between theunderside of the fastener head and the adjacent extremity of the sleeve.To provide a fastener which will accommodate work of increasedthickness, and it is only necessary to shift the core member 40 to theright as shown in FIG. 8, thereby increasing the distance A. Thedistance indicated by the letter B remains constant. It will be apparentthat when the dimension A is increased as shown in FIG. 8, the axialextent of the shank enlargement also increases. This axial enlargementin FIG. 8, designated by the numeral 200.

Obviously, the present invention is not limited to a fastener having thehead structure shown in FIGS. 1 to 8 inclusive, but contemplates othershapes and configurations. In FIG. 9, for example, the head of thefastener includes a section 44 for resiliently gripping a conduit orcable. In all other respects the fastener shank member shown in FIG. 9is similar to the previously described structure.

From the foregoing description it will be appreciated that the presentinvention'contemplates a multi-piece snap-in type fastener of verypractical design which is readily adaptable for accommodating work ofvarying thickness. By practicing the teaching of the present invention,including the simple expedient of varying the position of the corewithin the longitudinal opening in the mold, the cost of producingfasteners is reduced to a minimum. The shear strength and lateralstability of the fastener shank is increased by the provision of theenlarged shank portion, and as the thickness of the work increases, thelength of the enlarged shank portion also increases. The sleeve issecured against tilting or canting with respect to the shank by thelongitudinal protuberances or ribs on the inner wall of the sleeve. Thusthe lateral stability of the fastener within a work aperture is assured.

I claim:

1. A snapin type composite fastener for telescopic association as a unitwith a work aperture, including a shank, an integral head section at oneextremity thereof providing a work engaging surface, peripheral shouldermeans on said shank spaced axially from said work engaging surface andfacing toward the entering end of the shank, an open ended resilientsleeve member having a circumferentially continuous peripherytelescopically associated with said shank and with the periphery of thesleeve member tapering from a larger dimension adjacent the head to asmaller dimension adjacent the entering end of the shank, internalshoulder means adjacent the entering extremity of said sleeve memberabutting the aforesaid peripheral shoulder means to position said sleevea predetermined distance from said work engaging surface and to preventshifting of the sleeve member toward the head, laterally yieldableperipheral work engaging protuberant shoulder means at the trailing endof said sleeve spaced at predetermined distance from the aforesaid workengaging surface, said laterally yieldable shoulder means normallyprojecting radially outwardly beyond a circumference defined by themaximum diameter of said shank, and abutment means integral with theshank and abruptly angled to at least approach a position generallynormal to the shank axis for engaging a complemental surface on thesleeve member in advance of the smaller dimension thereof to preventunauthorized axial separation thereof from the entering extremity of theshank and thus prevent removal of the shank from the sleeve member inthe direction of the larger diameter thereof.

2. A snap-in type fastener for telescopic association with a workaperture as set forth in claim 1, wherein the shank includes anenlargement adjacent the head conforming substantially with the size ofthe work aperture which is to accommodate the fastener.

3. A snap in type fastener for telescopic association with a workaperture as set forth in claim 1, wherein the outer margin of the headsection is yieldable axially to facilitate aggressive impingement of thehead with a work surface upon complete insertion of the fastener shankwithin a work aperture.

4. A snapin type fastener for telescopic association with a workaperture as set forth in claim 1, wherein the laterally yieldable workengaging shoulder means comprise radial protuberances circumferentially.spaced uniformly.

5. A snap-in type fastener for telescopic association with a workaperture as set forth in claim 1, wherein protuberant means extendradially inwardly from the sleeve for engaging the periphery of theshank.

6. A snap-in type fastener for telescopic association with a workaperture as set forth in claim 5, wherein the protuberant meansextending inwardly from the sleeve comprise elements which are uniformlyspaced circumferentially and are located intermediate laterallyyieldably circumferentially spaced peripheral work engaging shouldersextending radially outwardly from the sleeve body.

7. A snap-in type fastener as claimed in claim 1, wherein axiallyextending external ribs on the sleeve member present the laterallyyieldable work engaging shoulder means.

8. A snap-in type fastener as claimed in claim 7, wherein the ribs taperinwardly substantially to the smaller dimension of the sleeve member.

1. A snap-in type composite fastener for telescopic association as aunit with a work aperture, including a shank, an integral head sectionat one extremity thereof providing a work engaging surface, peripheralshoulder means on said shank spaced axially from said work engagingsurface and facing toward the entering end of the shank, an open endedresilient sleeve member having a circumferentially continuous peripherytelescopically associated with said shank and with the periphery of thesleeve member tapering from a larger dimension adjacent the head to asmaller dimension adjacent the entering end of the shank, internalshoulder means adjacent the entering extremity of said sleeve memberabutting the aforesaid peripheral shoulder means to position said sleevea predetermined distance from said work engaging surface and to preventshifting of the sleeve member toward the head, laterally yieldableperipheral work engaging protuberant shoulder means at the trailing endof said sleeve spaced a predetermined distance from the aforesaid workengaging surface, said laterally yieldable shoulder means normallyprojecting radially outwardly beyond a circumference defined by themaximum diameter of said shank, and abutment means integral with theshank and abruptly angled to at least approach a position generallynormal to the shank axis for engaging a complemental surface on thesleeve member in advance of the smaller dimension thereof to preventunauthorized axial separation thereof from the entering extremity of theshank and thus prevent removal of the shank from the sleeve member inthe direction of the larger diameter thereof.
 2. A snap-in type fastenerfor telescopic association with a work aperture as set forth in claim 1,wherein the shank includes an enlargement adjacent the head conformingsubstantially with the size of the work aperture which is to accommodatethe fastener.
 3. A snap-in type fastener for telescopic association witha work aperture as set forth in claim 1, wherein the outer margin of thehead section is yieldable axially to facilitate aggressive impingementof the head with a work surface upon complete insertion of the fastenershank within a work aperture.
 4. A snap-in type fastener for telescopicassociation with a work aperture as set forth in claim 1, wherein thelaterally yieldable work engaging shoulder means comprise radialprotuberances circumferentially spaced uniformly.
 5. A snap-in typefastener for telescopic association with a work aperture as set forth inclaim 1, wherein protuberant means extend radially inwardly from thesleeve for engaging the periphery of the shank.
 6. A snap-in typefastener for telescopic association with a work aperture as set forth inclaim 5, wherein the protuberant means extending inwardly from thesleeve comprise elements which are uniformly spaced circumferentiallyand are located intermediate laterally yieldably circumferentiallyspaced peripheral work engaging shoulders extending radially outwardlyfrom the sleeve body.
 7. A snap-in type fastener as claimed in claim 1,wherein axially extending external ribs on the sleeve member present thelaterally yieldable work engaging shoulder means.
 8. A snap-in typefastener as claimed in claim 7, wherein the ribs taper inwardlysubstantially to the smaller dimension of the sleeve member.